How do you model and simulate the air gap around the hot nozzle?

[Anonymous]

Hello!

I need help in the following subject: How do you model and simulate the air gap around the hot nozzle? 

Do I have to create the air grap as a positive model in my CAD software? And after that do I have to create a new material in Moldflow, which would be air? And then do I have to assign this new material (air) to the air gap in Moldflow? 

Or does it a special option in the Moldflow, which simulate the air gap around the hot nozzle?

I hope you can help me!

Thanks a lot,

Daniel

[MartinCavalry]

Hi Daniel,

do you actually mean air around the runner or air gap between the runner and mould?

suppose you have your part and runner only, then try to change the runner heat properties. For the option as below, I dont need  an other model for air.
Select your relevant runner elements and right mouse click, Properties button.
Then define the "Heat loss into mold option" and I guess "Insulating properties" is the one for you.
There you can set you air gap distance.

hope this helps.

Best regards

[Anonymous]

Dear Martin!

Unfortunately this will not work for me, because the air gap is not around the hot runner. In my modell the air is around the heater element of the hot sprue. And the heater element properties don't have any heat loss option. 

Any idea?

Cheers,

Daniel

[MartinCavalry]

Hello Daniel,

OK I see, to work around this difficulty you could try modeling the air as a solid geometry like it was a mould around your heater.
For that you`d need to create a mouldbase around your heater and replace the mould`s thermal properties (rho, Cp,k) to air`s ones.
Not quite sure if you`ll get sensible results but this option maybe worth a try.

best regards

Martin

[Anonymous]

Dear Martin!

Yes, that's what I wanted to try! Bye the way thanks the comments and the help!

Best wishes,

Dániel Kiss